The present invention relates to heart valve replacement and, in particular, to collapsible prosthetic heart valves. More particularly, the present invention relates to devices and methods for repositioning of collapsible prosthetic heart valves.
Prosthetic heart valves that are collapsible to a relatively small circumferential size can be delivered into a patient less invasively than valves that are not collapsible. For example, a collapsible valve may be delivered into a patient via a tube-like delivery apparatus such as a catheter, a trocar, a laparoscopic instrument, or the like. This collapsibility can avoid the need for a more invasive procedure such as full open-chest, open-heart surgery.
Collapsible prosthetic heart valves typically take the form of a valve structure mounted on a stent. There are two types of stents on which the valve structures are ordinarily mounted: a self-expanding stent or a balloon-expandable stent. To place such valves into a delivery apparatus and ultimately into a patient, the valve must first be collapsed or crimped to reduce its circumferential size.
When a collapsed prosthetic valve has reached the desired implant site in the patient (e.g., at or near the annulus of the patient's heart valve that is to be replaced by the prosthetic valve), the prosthetic valve can be deployed or released from the delivery apparatus and re-expanded to full operating size. For balloon-expandable valves, this generally involves releasing the entire valve, and then expanding a balloon positioned within the valve stent. For self-expanding valves, on the other hand, the stent automatically expands as the sheath covering the valve is withdrawn.
Despite the various improvements that have been made to the collapsible prosthetic heart valve delivery process, conventional delivery devices, systems, and methods suffer from several shortcomings. For example, in conventional delivery devices for self-expanding valves, clinical success of the valve is dependent on accurate positioning, anchoring and acceptable valve performance. Inaccurate positioning increases risks such as valve migration, which may result in severe complications due to obstruction of the left ventricular outflow tract and may even result in patient death. Inaccurate positioning may further limit proper performance of the valve assembly. Additionally, improper positioning of a prosthetic heart valve may cause extended compression and/or stent deformation that affect valve durability.
In conventional devices, once the prosthetic heart valve has been fully deployed, it is difficult to reposition the valve without resheathing the valve and redeploying. One risk in repositioning a fully deployed valve is pushing the prosthetic heart valve into a dangerous location such as, for example, the ascending aorta due to lack of control.
There, therefore, is a need for further improvements to the devices, systems, and methods for transcatheter delivery and positioning of collapsible prosthetic heart valves. Specifically, there is a need for further improvements to the devices, systems, and methods for accurately positioning a prosthetic heart valve within the vasculature of a patient. Such positioning devices will help to reduce the risks associated with valve migration and improper valve positioning. Among other advantages, the present invention may address one or more of these needs.